The present invention relates to a method of producing a ternary chalocogenide single crystal. More particularly, the present invention is directed to a method of growing large, high-quality single crystals of Cadmium-Indium-Telluride (CdIn.sub.2 Te.sub.4) using an off-stochiometric melt based on the phase equilibrium relationship in the system CdTe-In.sub.2 Te.sub.3. The method of the present invention produces large high-quality single crystals of CdIn.sub.2 Te.sub.4 of a size previously unattainable by prior art methods. The crystals so produced have a large electro-optic coefficient and thus are well suited for application in electro-optic devices.
Though prior art methods are known to have been successful at producing Cadmium-Indium-Telluride crystals in the past, such prior art techniques have not been successful at producing crystals of sufficient size or purity for use in electro-optic applications. In fact, prior art crystals have been of insufficient size and quality to even enable researchers to determine the existence and extent of their electro-optic properties. Typically, prior art growth was accomplished by the Czochralski technique wherein a crystal was pulled from a melt of the same composition as the crystal. Because the melt composition is incongruently melting, it is difficult if not impossible to obtain a high-purity crystal free of precipitates through the Czochralski technique. Additionally, the Czochralski method does not incorporate the use of overpressures of the more volatile components of the melt and thus allows loss of these components from the solid growing crystal. As a result, the stoichiometry of the final crystal can change and hence, the electrical and optical properties of the crystal are correspondingly altered as a result.
Accordingly, it is a principal object of the present invention to provide a method for growing large, high-quality single crystals of high-purity CdIn.sub.2 Te.sub.4 to assure optimum electrical and optical properties. It is a further object of the present invention to provide a method for growing high-quality single crystals of CdIn.sub.2 Te.sub.4 to previously unattainable dimensions in order to provide crystals of sufficient size for research applications and use in electro-optic devices.